Mechanical fastening systems, of the type otherwise referred to as hook and loop fastener systems, have become increasingly widely used in various consumer and industrial applications. A few examples of such applications include disposable personal care absorbent articles, clothing, sporting goods equipment, and a wide variety of other miscellaneous articles. Typically, such hook and loop fastening systems are employed in situations where a refastenable connection between two or more materials or articles is desired. These mechanical fastening systems have in many cases replaced other conventional devices used for making such refastenable connections, such as buttons, buckles, zippers, and the like.
Mechanical fastening systems typically employ two components, a male (hook) component and a female (loop) component. The hook component usually includes a plurality of semi-rigid, hook-shaped elements anchored or connected to a base material. The loop component generally includes a resilient backing material from which a plurality of upstanding loops project. The hook-shaped elements of the hook component are designed to engage the loops of the loop material, thereby forming mechanical bonds between the hook and loop elements of the two components. These mechanical bonds function to prevent separation of the respective components during normal use. Such mechanical fastening systems are designed to avoid separation of the hook and loop components by application of a shear force or stress, which is applied in a plane parallel to or defined by the connected surfaces of the hook and loop components, as well as certain peel forces or stresses. However, application of a peeling force in a direction generally perpendicular or normal to the plane defined by the connected surfaces of the hook and loop components can cause separation of the hook elements from the loop elements, for example, by breaking the loop elements and thereby releasing the engaged hook elements, or by bending the resilient hook elements until the hook elements disengage the loop elements.
Mechanical fastening systems can be advantageously employed in disposable personal care absorbent articles, such as disposable diapers, disposable garments, disposable incontinence products, and the like. Such disposable products generally are single-use items which are discarded after a relatively short period of use, usually a period of hours, and are not intended to be washed and reused. As a result, it is desirable to avoid expensive components in the design of such products. Thus, to the extent that the hook and loop components are employed in such products, the hook and loop components need to be relatively inexpensive in terms of both the materials used and the manufacturing processes for making these components. On the other hand, the hook and loop components must have sufficient structural integrity and resiliency to withstand the forces applied thereto during normal wear of the absorbent article, in order to avoid potentially embarrassing situations for the wearer that can result from premature separation or disengagement of the hook and loop components.
U.S. Pat. No. 4,761,318 to Ott et al. discloses a loop fastening material useful in a mechanical fastening system for disposable articles. The loop fastening material disclosed by this patent includes a fibrous layer having a plurality of loops on a first surface adapted to be releasably engaged by a mating hook fastener portion and a layer of thermoplastic resin adhered to a second surface of the fibrous structure opposite the first surface. The thermoplastic resin anchors the loops in the fibrous structure.
U.S. Pat. No. 5,032,122 to Noel et al. discloses a loop fastening material useful in a mechanical fastening system for a disposable article. The loop fastening material disclosed by this patent includes a backing of orientable material and a multiplicity of fibrous elements extending from the backing. The fibrous elements are formed by continuous filaments positioned on and intermittently secured to the backing when the orientable material of the backing is in its dimensionally unstable state. The fibrous elements are formed by the shirring of the filaments between spaced, fixed regions of securement to the backing when the orientable material is caused to be transformed to its dimensionally stable state such that it is caused to contract or gather along its path of response. Thus, the loop material of this patent requires a backing of orientable material, such as an elastic or elastomeric or heat shrinkable material, that is caused to be transformed from a dimensionally stable state to a dimensionally unstable state and returned it to its dimensionally stable state.
U.S. Pat. No. 5,133,707 to Rogers et al. discloses a composite adhesive fastening tape and tape system for interconnecting printed surfaces, which includes a transparent main film portion with an embossed surface defined logo or symbol or the like and coated on one surface with an adhesive, in the tape system is included a target film portion, which target film portion is optionally decorated by colored numbers, letters, patterns, shapes or figures.
U.S. Pat. No. 5,326,612 to Goulait discloses another a loop fastening material useful in a mechanical fastening system for a disposable article. The loop fastening material disclosed by this patent includes a nonwoven web secured to a backing. The nonwoven web serves to admit and entangle the hooks of a complementary hook component. The nonwoven web has a specified basis weight range of between about 5 to about 42 g/m2, an inter-fiber bond area of less than about 10 percent, and a total plan view bonded area of less than about 35 percent.
U.S. Pat. No. 5,858,515 to Stokes et al., herein incorporated by reference, discloses a pattern-unbonded nonwoven fabric having continuous bonded areas defining a plurality of discrete unbonded areas, which is suitable for use as an improved loop fastening material for hook and loop fastening systems. The fibers or filaments within the discrete unbonded areas are dimensionally stabilized by the continuous bonded areas that encircle or surround each unbonded area. The spaces between fibers or filaments within the unbonded areas remain sufficiently open or large to receive and engage hook elements of a complementary hook material. The hook material is any of a wide variety of commercially available hook components which include a base material from which a plurality of hook elements project. Stokes et al. further describe a process for making such a pattern-unbonded nonwoven fabric including the steps of providing a nonwoven fabric or web, providing opposedly positioned first and second calender rolls and defining a nip therebetween, with at least one of the rolls being heated and having a bonding pattern on its outermost surface comprising a continuous pattern of land areas defining a plurality of discrete recesses, apertures or holes, and passing the nonwoven fabric or web within the nip formed by said rolls.
Notwithstanding the teachings of the aforementioned references, the need nonetheless exists for an improved pattern-unbonded, nonwoven fabric. Moreover, there still exists a need for an improved region of a web or fabric including loop fastening material for a mechanical fastening system, particularly as such are used in disposable personal care absorbent articles.